RESEARCH Friedrich G. Barth

Medium flow reception

Over the past years much of our research concentrated on the analysis of air movement detection, bringing together biology and engineering (Professor JAC Humphrey, Dep´t of Mechanical Engineering, University of Virginia) in an effort to quantitatively model the air hair interaction and to understand both the mechanical and physiological properties of the sensors (spider trichobothria as the case in point) in relation to behavior (prey capture induced by air movement). More recent efforts concentrate on the question of the ontogeny of prey signal localisation (with Sophia Ungersböck) and the mechanical interaction between trichobothria forming a group (with Brice Bathellier, JAC Humphrey and Jörg Albert).

Touch reception

Another interest is touch reception which has never been studied in detail in arthropods. We are intrigued by the diversity of the several 10.000 mechanosensitive hairs covering the cuticular surface of Cupiennius. Again, the collaboration with engineers (Professor FG Rammerstorfer, Dipl.Ing.H-E Dechant, Dep´t of Lightweight and Aerospace Engineering, Technical University Vienna) and the application of micromechanical measurements and finite element analysis uncovered a surprisingly sophisticated design of selected tactile spider hairs. Behavioral and electrophysiological studies (with Jörg Albert and Oliver Friedrich) as well as fine structural work (with Stefan Nemeth) on the biology side not only elucidated functional characteristics of tactile hairs per se but also deepened our understanding of the diversity of arthropod mechanosensitive hair design, which ranges from that of extremely sensitive wind sensors to that of much more robust tactile sensors. Current work deals with the characteriszation of proprioceptive hairs (with Clemens Schaber).

Force sensors

New developments in technology will allow us a fresh look at a sensory system which we have been studying in some detail previously: Force (strain) detectors embedded in the arthropod exoskeleton, especially spider slit sensilla. The goal of our new efforts is to better understand the tricks contained in the diversity of arrangements of groups of slits as lyriform organs and their functional significance. This again needs close cooperation with engineering (Professors FG Rammerstorfer, Böhm, Eberhardsteiner and Dipl.Ing. B. Hößl , Technical University Vienna) for quantitative modelling of the sensory organs. It also needs the intracellular recording and identification of the variously arranged slits in a lyriform organ (with Dr. Jorge Molina and Anna-Maria Burger) and the reconstruction of their threedimensional morphology (with Rainer Müllan). For references to our previous work on slit sensilla

Stingless bees: recruitment and communication

We have been following this research line for several years in collaboration with Professor R. Zucchi at the University of São Paulo / Ribeirão Preto ( where we can work with a number of species of stingless bees) and with Professor W. Francke of the University of Hamburg who is helping with chemical analyses. In short the goal of this research is to better understand the mechanisms underlying communication serving the recruitment of nestmates. Currently two Ph.D. students (Mag. Veronika Schmidt and Mag. Dirk Louis Schorkopf) and a post doc (Dr. Michael Hrncir) are involved in this work. Two Ph.D.s (Michael Hrncir, Stefan Jarau) and a Diploma student (Sigrid Allerstorfer) recently finished their work. For details on our bee work

Spider photoreceptor cells

Spatial and temporal resolution of spider eye photoreceptor cells is currently studied in Lund by Karin Pirhofer in collaboration with Professor Eric Warrant. The main idea behind these experiments is to clarify the relation between photoreceptor properties, eye muscle movements and motion detection.